The present invention relates to a bodily implant, in particular a stent, for insertion into a living body, having good X-ray visibility, and a method for manufacturing a marker element for increasing the X-ray visibility, and a method for manufacturing a bodily implant.
Bodily implants or stents of this type protect channels in living bodies, such as blood vessels, the esophagus, the urethra, or renal passages, for example, by insertion of the stent and expansion of same inside the bodily channel. In this manner collapse or occlusion of the particular bodily channel may be prevented. A stent is also used, for example, for intercerebral aneurysms, which are the most common cause of non-traumatic subarachnoid hemorrhages. The incidence occurs in 1% of the general population, and, according to autopsy studies, as high as 9%. From a pathomorphological standpoint, intracerebral aneurysms as a rule are genuine saccular aneurysms which are usually localized in vascular arborizations (see, for example, Schumacher, M., “Diagnostic workup in cerebral aneurysms” in Nakstadt PHj (ed.): “Cerebral Aneurysms,” pp. 13-24, Bologna: Centauro (2000)).
Such bodily implants or stents may also be used as carriers for medications to enable local therapy within the bodily channel. These stents are inserted in a collapsed state into a bodily channel, and are expanded after being positioned in the bodily channel. The stents are usually composed of stainless steel or a cobalt-chromium-tantalum alloy. The stents may be inserted into the bodily channel by means of an expansion device, a balloon catheter, for example, and are expanded there.
However, the stents may also be composed of other materials, for example polymers, self-degradable materials such as lactic acid materials or derivatives thereof, in addition to nitinol (nickel-titanium alloys) and/or other self-expanding materials such as so-called shape memory materials. To increase the X-ray visibility of these stents, the stents are often provided with additional elements (known as markers) which are produced from a material having high X-ray visibility.
Gold or a gold alloy is a particularly suitable material for the markers, since gold has very good X-ray visibility. Markers are also produced from tantalum, but its X-ray visibility is not as satisfactory as that of gold. However, gold has the disadvantage that it is less resistant to corrosion than tantalum.